Getting started

We will use the Poké Ball example here. You need at least 3 apricorns. Cook them and get cooked apricorns.
The next step is creating a lid. You create a Poké Ball disc by putting 3 cooked apricorns in a horizontal fashion. Note: Different Poké Balls use different combinations of apricorns. See the page to the Poké Balls you are trying to craft to see the recipe.

Crafting it

To craft the Poké Ball itself, you need an Anvil and a hammer. Right click the anvil with a disc in your hand to place it and start hitting the anvil with a hammer (left clicking it), and after a while it will turn into a lid/Iron base.

To create the Poké Ball itself, you need the iron base, a button, and the Poké Ball Lid. Put them anywhere in the crafting table.